I have a bit of a situation coming up. Due to a complete website structure redesign that is basically inevitable, I expect to have the following:

• Our sitemap of about 12,000 url's have about 90-95% of them change
• Out of those 12,000, I expect around 5000-6000 internal links to go dead in the process.
• No external links to this site yet, as it is still in development.

Is there a tool out there that can do the following:

• I can feed the sitemap.xml after the restructuring
• have it parse each pages links for 404 errors on that page
• only report the pages/errors, preferably with just the url it is on, the url of the error, and the anchor text

I have found a few tools, but all of them seem to be limited to 100 pages.

Any advice for an intermediate webmaster to help this situation? 301 redirects are not viable in this situation.